Underwater acoustic sensor networks (UWASNs) are complex in design due to the characteristics of underwater medium. The underwater communication environment and the medium vary on time, geographical location and depth. Sensor nodes are also born with some limitations such as fixed amount of energy, small size memory and node mobility. Signals travel inside a noisy acoustic channel which required checking errors after receiving. Secure communication is one of the main characteristics of any networks. UWASNs also maintain a security protocols in each layer. Moreover, data link layer performs the main task of error check. To protect unauthorized access to our network and for a common line of defense against the errors, it requires attentions during the protocol design. Depends on the several error detection mechanisms, cyclic redundancy check (CRC) performs better than other mechanisms in respects of the different underwater factors. In this paper, we discuss about the CRC: how it is different from other mechanisms in terms of carrying functions that helps to check double error (running sum) but correct checksum. The trade-offs between error detection system designs (using a nibble size CRC) and underwater communication system designs.